Lithium Hexamethyldisilazide → (Rs)-(e)-methyl 4-[3-(4,4-dimethyl-thiochroman-6-yl)-oct-1-enyl]-benzoate

Participants

Reaction Steps

0.51 g of methyl 4-(diethoxyphosphorylmethyl)-benzoate were dissolved in 7.5 ml THF and treated, at −20° C., with 1.8 ml of a 1M solution of lithium bis(trimethylsilyl)amide in hexane. After 15 min. at −20° C., a solution of 350 mg of (RS)-2-(4,4-dimethyl-thiochroman-6-yl)-heptanal in 7.5 ml THF was added. The reaction mixture was stirred at room temperature for 1.5 hour. The mixture quenched by the addition of 10 ml of water and the resulting mixture was partitioned in 25 ml ethyl acetate/15 ml sat. aq. sodium chloride solution. The phases were separated and the organic phase was dried over MgSO4. The solvent was removed in vacuo and the crude product was purified by flash chromatography (SiO2, 10% ethyl acetate/hexanes), giving 200 mg of the corresponding ester. 1H NMR (CDCl3): 7.94 (d, J=8.5 Hz, 2H), 7.38 (d, J=8.5 Hz, 2H), 7.19 (d, J=1.8 Hz, 1H), 7.03 (d, J=8.1 Hz, 1H), 6.91 (dd, J=8.1, 1.8 Hz, 1H), 6.45 (d, J=15.9 Hz, 1H), 6.38 (d, J=15.9 Hz, 1H), 3.90 (s, 3H), 3.30 (m, 1H), 3.05-3.00 (m, 2H), 2.00-1.90 (m, 2H), 1.85-1.75 (m, 2H), 1.33 (s, 6H), 1.40-1.30 (m, 6H), 0.86 (t, J=6.5 HZ, 3H).

Provenance & Evidence